Car safety systems and technologies have advanced incredibly over the past five decades, but one simple lifesaving device - the three-point seat belt - has remained largely unchanged since it was invented more than fifty years ago. Research has shown that seat belts can reduce the risk of injury in a crash by at least 90 per cent. But there are still some misconceptions about seat belt use. Here's how your seat belt keeps you safer and what you need to know about wearing one.

How they work

Seat belts keep you in your seat if the car hits something or rolls over. The seat belt prevents you from being thrown about inside the car, striking against hard surfaces, hitting other occupants or being thrown out of the car. The forces involved in a crash are much too high for you to resist simply by bracing yourself.

What is the force of a crash like?

If a car travelling along the road at 60km/h hits an object, anything unrestrained (including you if you’re not wearing a seat belt) keeps travelling at 60km/h until it hits something. If you hit the windscreen, you will suffer severe, possibly fatal, injuries.

Modern cars are designed so that the front and rear crumple on impact, and the passenger cabin stays rigid. This reduces the force of impact and the vehicle takes longer to slow down.

Why is this important? Think about diving into water compared to falling on concrete. When you dive into water, your speed is reduced by the resistance of the water over a distance of one to two metres. If you fall onto concrete you stop within millimetres.

Seat belts act in a similar way. Wearing a seat belt means you slow down with the car over several metres, rather than just millimetres if you hit the windscreen or dashboard. Injuries are therefore greatly reduced.

Using seat belts

Seat belts should be worn tight but comfortable, with the buckle at the side. The webbing should not have any twists or knots. If the seat belt has an adjustable top mounting it should be set level with your ear.

Pregnant women should wear a seat belt across the hips and below the baby.

Fact vs fiction

Even though non-seat belt wearers are ten times more likely to be killed or severely injured in a crash, there are a number of misconceptions about seat belts:

Perception: You could be trapped in the car by your belt.
Reality: Real-life experience shows that this rarely happens. Use of a seat belt means you’re more likely to be conscious and able to get out of the vehicle after a crash.

Perception: Seat belts prevent you from being thrown clear.
Reality: You’re more likely to be killed if you’re thrown out of the vehicle.

Perception: You don’t need to wear a seat belt for short trips.
Reality: Most crashes occur within 5km of home.

Children and car restraints

Approximately 150 children are admitted annually to Perth Children’s Hospital as a result of a road traffic injury, according to Kidsafe WA. Tragically, vehicle crashes remain the leading cause of death for children aged 0-14 years. 

When fitting your child car restraint, it’s important to follow the manufacturer's instructions to ensure it's safely fitted. Ideally you should choose to have it professionally fitted.

For children aged up to six months, a rearward-facing restraint (e.g., infant capsule) must be used.

Children between six months and up to four years of age must either sit in a rearward-facing restraint or a forward-facing restraint that has an inbuilt harness. 

Children under four years of age must not be in the front row of seats in a vehicle that has two or more rows of seats.

From four to under seven years of age, a child should remain in a forward-facing restraint with an inbuilt harness or switch to a booster seat with a properly fastened lap and sash seat belt or lap seat belt and child harness. Even at this age, a child must not be in the front row of seats if there are two or more rows, unless the seats behind are occupied by children under seven years old, or the seat’s not suitable a forward-facing restraint or booster seat to be installed.

While the law focuses on age, it does require children to transition to the next applicable restraint requirement, if the child is too big or tall to be safely restrained in the one for their age group.

Once the child reaches seven years of age, parents must assess whether they are big enough to safely use an adult seat belt or should remain in the child restraint. It’s recommended you follow the ‘5 Step Test’ on the Kidsafe WA website to determine whether they’ve outgrown the necessary points of contact.

A seat belt is still effective for pregnant women and is required by law. You should place the lap-belt as low as possible under the baby, so it sits over the upper thighs and pelvis.

Holding children in your arms is dangerous and illegal, as is two or more people sharing the same seat belt.

RELATED: Choosing the right child car restraint »

Legal requirements

Under the Road Traffic Code 2000 (WA), all drivers and passengers (who do not have an exemption or legal defence as outlined below), must wear a seat belt where provided.

Seats with seat belts should be occupied in preference to those without.

There are some exemptions. For example, you do not have to wear a seat belt if you are:

  • Hold a current medical certificate, signed by a medical practitioner, giving you exemption.
  • Doing work which requires you to get in and out, or on or off, a vehicle frequently (e.g., you can show you are engaging in the door-to-door delivery or collection of goods, or in the collection of waste or garbage) and the vehicle speed does not exceed 25km/h.
  • Under the age of one year and in a passenger transport vehicle (e.g., on-demand, tourism and regular passenger transport services), if there is no suitable child restraint available and if the passenger is not in the front row of seats in instances where there are two or more rows of seats.
  • A taxi driver carrying one or more passengers (for reward) during the hours of darkness.
  • Providing or receiving urgent and necessary medical treatment.
  • Being lawfully detained by an officer of a detention centre or an officer of a prison.
  • In a seat that is not fitted with a seat belt, and there is no requirement for that seat to be fitted with a seatbelt, and all passengers who are exempt or have a defence to being charged with not wearing a seatbelt are not occupying a seat with a seatbelt or restraint that could be used by a passenger who is required to use one.
A close up of a seat belt clicked into place
Make sure your seat belt is always clicked into place

There are other exemptions for emergency services personnel, people in custody, bus drivers, those solely (or principally) using a vehicle for agricultural or farming activities, etc. as outlined in regulation 284 of the Code.

Seat belts are designed to be used by only one person at a time. Doubling up, fastening a seatbelt around two people is both illegal and unsafe.

Damaged or frayed seat belts must be replaced; as should seat belts that have been worn in a severe crash.

To get more information on the rules and regulations relating to seat belts and restraints, contact the Road Safety Commission or Department of Transport.

The history of seat belts

Seat belts are not new: Volvo introduced todays' three-point seat belts as standard in 1959. They also made the system available to all car manufacturers, patent-free - a generous act which has saved countless lives since then.

In Australia, front-seat seat belts became compulsory in 1969, and belts were required on all seats by 1971. It’s also been compulsory to wear a seat belt since 1971.

Early seat belts relied on the give in the webbing material, but there were two major issues. First, the webbing was too loose, so the occupant could move forward in a crash and possibly make contact with the dashboard or windscreen, or they could be injured by the sudden jerk when the slack in the webbing stopped. Second, in severe crashes the loads imposed on the body could become too high, leading to injury.

The first problem was solved in 1975 when automatic retractors were made compulsory – along with pre-tensioners, they were added to take up the slack in the seat belt.

Webbing clamps were later introduced to prevent excessive payout of the webbing if the retractor locking is delayed. Load limiters allow limited webbing payout when crash loads become excessive.

Modern cars feature airbags and electronics that work with intelligent seat belt design to allow for a greater variety of situations, while warning systems remind drivers and passengers to wear seat belts. These innovations have greatly improved safety for drivers and passengers.

Last updated January 2022